Electrode mounting for electron discharge devices



Feb 1947. J. J. BORZIN ETAL ELECTRODE MOUNTING FOR ELECTRON DISCHARGE DEVICES Filed June 14, 19 15 a 1 SN W x WWW n 1 mi N 5 H WBM W Z IJGHWA A m,

1 JEEZZZZ Fatented Feb. 18, 1947 ELECTRODE MOUNTING FOR ELECTRON DHSCHARGE DEVICES John J. Borzin, Newark, and William G. Moran, Bloomfield, N. 3., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application June 14, 1945, Serial No. 599,412

2 Claims.

This invention relates to electron discharge devices and more particularly to such as are intended for and capable of handling large amounts of power.

In devices of the general character indicated above, it is a common practice to provide support and lead-in connections at opposite ends of the tube. Mechanical dimculty is experienced with such tubes in obtaining and maintaining coaxial alignment of the several electrodes and at the same time to have a structure capable of convenient fabrication and rapid but accurate assemblageu Accordingly, an object of the present invention is to obtain an electron discharge device with opposed stems which is readily assembled.

Another object of the invention is to obtain axial alignment and rigidity of electrodes capable of such ready assembly.

Other objects of the invention will appear to those skilled in the art to which it appertains both by direct recitation thereof as the description proceeds and by implication from the context.

Referring to the accompanying drawing in which like numerals of reference indicate similar parts throughout the several views:

Figure 1 is a sectionalelevation of an electron discharge device embodying the invention;

Figure 2 is a similar sectional elevation of the electrode structure and stems somewhat enlarged over Fig. 1 and at right angles to the showing of and on line IIII of Fig. 1;

Figure 3 is a cross-sectional view on line III-III of Fig. 1:, and

Figure 4 is an enlarged sectional elevation of the end portion of the electrodes and support therefor shown at the bottom part of Fig. 1.

In the specific embodiment of the invention illustrated in said drawing, the electron discharge device there shown provides a spiral or coiled filamentary cathode I!) through which extends an axially positioned support rod H. Outside of the cathode coil and coaxial therewith is a helical control grid l2, and, if desired, another but larger coaxial helical screen grid 13 may be provided. All these parts, namely the said cathode, its rod H and the two grids are supported from and have lead-in connection through one or the other or both of opposite end stems l 4, I5 formed as part of the glass It.

A coaxial anode l? is provided around a mid portion of the screen grid, this anode being shown as supported by and having lead-in connection through a stem l8 at the side of and formed as part of the said envelope. Other means of support for the anode, well known in the prior art, however, may be substituted.

Just as a matter of convenience, the descrip tion will refer to parts in their positions as appearing in the drawing, although it will be understood that the posture of the device is wholly arbitrary and might just as well have been with the other end up, horizontally or otherwise.

The particular cathode shown herein is a coiled wire filament the lead-in wires for which, according to the arbitrary location of parts men.- tioned above, are sealed through the upper stem I5, one of the filament lead-in wires being the aforementioned axially positioned support rod I l This rod extends through the middle of the upper stem and longitudinally through the cathode, terminating short of the opposite or bottom stem 14. The other or second lead-in wire 9 for the filament is at one side of said rod l l and, of course, insulated therefrom. Near the inner end of this second lead-in wire is is a ceramic or other spacer 20 through which the rod l I likewise extends, said spacer being suitably held in place and bracing the lead-in wires with respect to each other. Beyond the spacer 2E3 the filament is secured next the end of lead-in wire it, said filament being spiral and around rod H but spaced therefrom to the far end of the filament where the convolutions decrease in diameter so as to engage the end of the filament around the rod, as at 2 l where it is'welded or otherwise made secure but with the rod continuing therebeyond.

From the opposite stem ii, that is, the stem shown at the bottom of the envelope in Fig. 1, and extending through said stem, are sealed two support rods 22 of which one or both may be for lead-in purposes. The inner ends of these support rods are welded or otherwise seemed, as at 23, to corresponding two stay wires 24, of which there are four shown, and constituting part of control grid l2. By virtue of the use of several stays 2d longitudinally of the grid and welding of each convolution of the grid spiral winding to each stay, the grid is quite a rigid structure. The rods 22 by which the grid is supported are rigid and being rather widely separated aiiord good bracing for the grid to maintain its alinement even with rough treatment of the device. For additional bracing, a spacer 25 is provided on the said rods 22 between the stem l4 and proximate or lower end of grid It. This spacer is held by suitable means from movement longitudinally of the rods. Furthermore said spacer has a central hole therein through which aforementioned central rod ll may be slid during assembly and which therefore affords additional mutual bracing of the several rods from each other.

Screen grid I3 is shown as formed with a spiral winding around four stays 26 the length of which carries the end portions to situation juxtaposed to the sides of both stems l4, I5. Said stays are welded or otherwise secured to a clamp collar 21 at one end of the tube, the collar shown being around and tightened to grip stem I5. The other ends of the screen grid stays are yoked in pairs with resilient bands 28 that engage the side of stem l4 and thereby retain the screen grid substantially coaxial to the other electrodes and resist deflection of said grid even with rough usage.

It will be understood that the stems are separately fabricated and, with electrodes mounted therewith, finally assembled with the rest of envelope I6, evacuated and sealed. Central rod H and filament lead 19 are sealed in stem l5 and filament I is applied thereto while the stem is separate from the envelope. If screen grid I3 is to be incorporated in the device, it likewise is applied to stem I and clamped in axial alignment with the central rod and filament. A flexible connection 29 between one grid stay and a lead-in wire 39 is completed. After being properly positioned, the stem 15 is sealed to envelope 29.

Similarly, stem I4 is fabricated with the corn trol grid leads therein and the control grid is applied on the said leads before the stem is incorporated in the device. The anode I! is applied to its stem l8 and the stem sealed to the envelope. Then one of the other stems, for instance stem (5, is applied, inserting the screen grid, cathode and central rod through the anode. A side tap flexible lead 3! and external connector 32 may then be applied to afford external connection for the screen grid. Then the lower stem is applied by inserting the control grid axially into the screen grid and between the screen grid and cathode. As the stem approaches its final position, spacer comes to the end of central rod l I and caused to slide onto that rod until the control grid is at its proper longitudinal position. By virtue of the support from the spacer 25, it is a very simple matter to align the control grid, and this alignment is effected by engagement of the resilient bands of the screen grid with the stem and may require only slight alteration of position by the operator. The stem is sealed to the envelope and the exhaust, seasoning, sealing and like operations then performed to complete the device as usual in the art.

'We claim:

1. An electron discharge device comprising an envelope having stems at opposite ends thereof, a central rod projecting from one said stem, a cathode on said rod intermediate the ends there of, mounting means protruding from the other stem and including the outer end of said rod therebetween, an electrode on said mounting means, and a spacer on said mounting means between the electrode thereon and the stem from which said mounting means protrudes, said spacer receiving and engaging a part of said rod included between said mounting means.

2. An electron discharge device comprising an envelope having stems at opposite ends thereof, a central rod projecting from one said stem, a cathode on said rod intermediate the ends thereof, mounting means protruding from the other stem and including the outer end of said rod therebetween, an electrode on said mounting means, and a spacer on said mounting means between the electrode thereon and the stem from which said mounting means protrudes, said other stem.

JOHN J. BoRzIN. WILLIAM G. MORAN.

REFEnEucEs CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,912,006 Fischler May 30, 1933 2,099,579 Taylor Nov. 16, 1937 1,849,848 Murphy Mar. 15, 1932 1,980,804 Koch "Nov. 13, 1934 2,105,507 Ronci Jan. 18, 1938 1,993,804 Powers Mar. 12, 1935 

